Synthesis of 4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide through cycloaddition reaction of N-sulphinylanilines and N-(α-cyano-α-aryl) -methylanilines

Article abstract of DOI:10.1002/jhet.1828

Through the normal mode of cycloaddition reaction of N-(α-cyano- α-aryl)-methylanilines (II) onto N-sulphinylanilines (III) has provided 2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxides (IV). The present protocol has advantage of convenient operation to synthesize heterocyclics in good yield.

Full text of DOI:10.1002/jhet.1828

July 2014
Synthesis of 4-Imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide
through Cycloaddition Reaction of N-Sulphinylanilines and
N-(a-Cyano-a-aryl)-methylanilines
1157
*
Manpreet Kaur and Baldev Singh
Department of Chemistry, Punjabi University, Patiala 147002, Punjab, India
*
E-mail: singhbaldev1981@gmail.com
Received May 9, 2012
DOI 10.1002/jhet.1828
Published online 10 December 2013 in Wiley Online Library (wileyonlinelibrary.com).
Through the normal mode of cycloaddition reaction of N-(a-cyano-a-aryl)-methylanilines (II) onto
N-sulphinylanilines (III) has provided 2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxides (IV).
The present protocol has advantage of convenient operation to synthesize heterocyclics in good yield.
J. Heterocyclic Chem., 51, 1157 (2014).
INTRODUCTION
anhydrous toluene in the presence of catalytic amount of
anhydrous pyridine. The usual work-up of the reaction mixture
provided the crude product, which on recrystallization gave
pure product in good yield. These have been characterized as
2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide
N-Sulphinylanilines because of the presence of cumulative
double bonds and suitable polarity in bonds have been known
for the synthesis of new heterocyclic compounds [1]. The
2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide
has been synthesized successfully by the cycloaddition reac-
tion of N-sulphinylanilines acting as diene with substituted
benzalanilines [2,3] (Scheme 1). In an earlier report from
these laboratories, the Diels–Alder cycloaddition reaction of
N-sulphinylanilines acting as dienophiles with conjugated
open chain azomethines acting as diene has been reported [4].
1
(IV) through their melting point, elemental analysis, IR, H
NMR, 13C NMR, and mass spectra (Scheme 2). The reaction
seems to proceed by the initial attack of the lone pair of electrons
on the nitrogen atom of secondary amine on the electron-
deficient sulfur atom of N-sulphinylaniline, and cyclization
is completed by the subsequent attack of the heterocumulene
double bond at the carbon atom of the nitrile function,
followed by the loss of proton from the ammonium ion to pyr-
idine base. The iminium anion in turn takes up this proton from
the protonated base to give the cycloadduct (IV) (Scheme 2).
The infrared spectra of cycloadduct (IV) show absorp-
tion band at 3379 (>N–H), 1660–1616 (>C═N–), 1021
(>S═O), and 1632–1597 (aromatic >C═C) cmꢀ1 in addi-
tion to absorption bands because of other functions present.
These spectra lack the absorption band at 2236–2230 cmꢀ1
because of nitrile function, indicating that nitrile group has
enter into the cycloaddition reaction.
RESULT AND DISCUSSION
Presently, the cycloaddition reaction of N-sulphinylanilines
with N-(a-cyano-a-aryl)-methylanilines have been success-
fully carried out. The N-(a-cyano-a-aryl)-methylanilines
needed for the reaction have been synthesized through hydro-
cyanation of azomethines employing potassium cyanide in
aqueous ethanolic solution under acidic condition [5],
whereas the azomethines required for hydrocyanation were
synthesized by condensing aromatic aldehyde and aromatic
amines having both electron withdrawing and electron-
donating substituents on C-phenyl and N-phenyl moiety [6].
N-Sulphinylaniline used for cycloaddition reaction has been
synthesized by the reaction of thionyl chloride with aniline
[7,8]. In these dipolar cycloaddition, N-(a-cyano-a-aryl)-
methylanilines (II) act as a “dipole” and sulphinylanilines
(III) act as “dipolarophiles.” This cycloaddition reaction has
been carried out by the refluxing of N-(a-cyano-a-aryl)-
methylanilines with an excess of sulphinylanilines in
In the 400 MHz 1H NMR spectra of 3-(2-chlorophenyl)-
4-imino-5-phenyl-2-(2-methoxyphenyl)-2H,3H,5H-[1,2,5]
thiadiazolidin-1-oxide display a multiplet signal in the
region at d 7.8–6.7 (13H, Ar) has been assigned to aromatic
proton, a singlet in the region at d 4.6 (1H, >N–H) assigned
to imino proton. A singlet in the region at d 5.7 (1H, CH–)
assigned to the benzylic proton, this proton disappears on
deuterium exchange, whereas a sharp singlet in the region at
d 3.8 (3H, –OCH3) assigned to methoxy proton.
© 2013 HeteroCorporation

1158
M. Kaur and B. Singh
Vol 51
Scheme 1. Classical Synthesis of 4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide.
Scheme 2. Mechanistic pathway of 2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide.
In their 13C NMR spectra, compound 3-(20-chlorophenyl)-
EXPERIMENTAL
4-imino-5-phenyl-2-(200-methoxyphenyl)-2H,3H,5H-[1,2,5]
thiadiazolidin-1-oxide displays the signal at d 147.5 has been
assigned to imino carbon, signal at d 134.4 has been assigned
to etheric aromatic carbon, whereas carbon bearing chlorine
appears at d 133.5. The signals at d 130.9 and d 130.4 have
been assigned to aromatic carbon attached to nitrogen atom
and other signals at d 110.1–111.7, 117.8–119.8, and
121.2–128.8 have been assigned to carbon atom of aromatic
ring. The signal at d 47.5 has been assigned to carbon atom
of benzylic group, whereas the signal at d 55.5 assigned
to carbon atom of methoxy group. In the high resolution
mass spectra, 3-(20-chlorophenyl)-4-imino-5-phenyl-2-(200-
methoxyphenyl)-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide
display molecular ion peak at m/z 411 and others prominent
peaks are at m/z 271, 246 and, 212.
I. General procedure for the preparation of azo-
methines.
Variously substituted azomethines were prepared
by following an identical procedure as described in the literature
[5]. Synthesis of o-chlorobenzylidene-o-anisidine is described as a
representative case. Orthochlorobenzaldehyde 1.40 g (0.01mol)
was mixed with 1.23 g (0.01 mol) of o-anisidine in 10 cm3 of ethyl
alcohol. The reaction mixture after gentle warming provided the
required azomethines. Mp 78–80ꢁC.
II. General procedure for the preparation of N-(a-cyano-
a-aryl)-methylanilines. To the aqueous ethanolic solution of
azomethines 2.45 g (0.01 mol) taken in conical flask, an
equimolar quantity of sodium cyanide 1.06 g (0.01 mol) was
added along with the addition of glacial acetic acid (3–5 mL), in
a good ventilated hood. The flask was tightly corked and shaken
intermitantly for half an hour. The reaction mixture was kept for
overnight period. Usual work-up of reaction mixture provided
the crystalline product that was recrystallized from petroleum
ether. Mp 94–96ꢁC.
These cycloaddition reactions are regiospecific in nature
as all the cycloaddition reactions lead to the formation of
only one isomer in each case. It may be concluded that
the azomethines having electron donating as well as elec-
tron withdrawing groups in the N-phenyl ring and C-phenyl
ring undergo these cycloaddition reaction effectively.
III. General procedure for the preparation of 2,3,5-triaryl-
4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide. To N-(a-cyano-
a-aryl)-methylanilines (0.01 mol, 2.08 g), in anhydrous toluene
taken in a 100 mL round bottom flask, were added a few drops of
anhydrous pyridine and N-sulphinylanilines (0.015mol, 2.34 g) at
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2014
Synthesis of 4-Imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide through Cycloaddition
1159
Reaction of N-Sulphinylanilines and N-(a-Cyano-a-aryl)-methylanilines
room temperature. The reaction mixture was refluxed for 30–40 min
and was allowed to stand overnight. This, on addition of solvent
ether, gave a white product. The crude product was washed with
anhydrous ether and was recrystallized from alcohol–ether (1:1)
mixture to yield 3-(20-chlorophenyl)-4-imino-5-phenyl-2-(200-
methoxyphenyl)-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide in 67%
yield. Mp 85–87ꢁC. These thiadiazolidin-1-oxides have been
characterized through elemental analysis, IR, 1H NMR, 13C
NMR, and high resolution mass spectral data. All the
thiadiazolidin-1-oxides (IIa to IIs) were prepared by following an
identical procedure (Tables 1 and 2).
130.3, 131.4, 133.5, 134.3, 147.5; MS: Molecular ion peak m/z
426; Anal. Calcd for C20H15ClN4O3S: C, 56.27; H, 3.54; N,
13.12. Found: C, 56.12; H, 3.17; N, 13.12.
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(4-chlorophenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IId).
Yield: 64%; IR (Potassium bromide): 3344 (>N–H), 1035–1050
Mp 102–104ꢁC;
(S═O), 1635–1598 (aromatic >C═C<), 1686–1612 (>C═N–)cmꢀ1
;
1H NMR (400 MHz, CDCl3) d: 7.4–6.7 (13H, m, Ar), 4.1
(1H, s, >N–H), 5.6 (1H, s, CH–); 13CNMR (CDCl3) d: 48.1,
115.5, 117.4, 125.3, 127.8, 129.0, 129.5, 129.8, 130.5, 131.2,
131.8, 133.5, 143.1; MS: Molecular ion peak m/z 415; Anal.
Calcd for C20H15Cl2N3OS: C, 57.70; H, 3.63; N, 10.09. Found:
C, 57.23; H, 3.17; N, 10.02.
3-(2-Chlorophenyl)-4-imino-2,5-diphenyl-2H,3H,5H-[1,2,5]
thiadiazolidin-1-oxide (IIa).
(Potassium bromide): 3332 (>N–H), 1656 (>C═N–), 1632–1575
(aromatic >C═C<), 1023 (>S═O) cmꢀ1 1H NMR (400 MHz,
Mp 85–87ꢁC; Yield: 69%; IR
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(4-methoxyphenyl)-
2H,3H,5H-[1,2,5]thiadiazolodin-1-oxide (IIe). Mp 95–97ꢁC;
Yield: 68%; IR (Potassium bromide): 3337– (>N–H), 1024
;
CDCl3) d: 7.7–6.8 (14H, m, Ar), 4.2 (1H, s, >N–H), 5.6 (1H, s,
CH–); 13C NMR (CDCl3) d: 46.7, 111.3, 116.7, 118.2, 119.3,
121.7, 127.3, 129.2, 129.4, 130.3, 131.7, 133.2, 143.7; MS:
Molecular ion peak m/z 381; Anal. Calcd for C20H16ClN3OS: C,
62.90; H, 4.22; N, 11.00. Found: C, 62.83; H, 4.10; N, 11.02.
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(4-tolyl)-2H,3H,5H-
[1,2,5]thiadiazolidin-1-oxide (IIb). Mp 112–114ꢁC; Yield 67%;
IR (Potassium bromide): 3338 (>N–H), 1024 (>S═O), 1630–1585
(>S═O), 1630–1580 (aromatic >C═C<), 1665 (>C═N–) cmꢀ1
;
1H NMR (400 MHz, CDCl3) d: 7.9–6.8 (13H, m, Ar), 4.4 (1H, s,
>N–H), 5.6 (1H, s, CH–), 3.6 (3H, s, –OCH3); 13C NMR
(CDCl3) d: 46.0, 56.3, 110.2, 111.3, 116.4, 117.7, 119.6, 121.0,
126.7, 128.8, 129.0, 130.3, 130.7, 131.6, 133.3, 134.5, 147.7;
MS: Molecular ion peak m/z 411; Anal. Calcd for
C21H18ClN3O2S: C, 61.23; H, 4.40; N, 10.20. Found: C, 61.03;
H, 4.14; N, 10.03.
(aromatic >C═C), 1675 (>C═N–) cmꢀ1 1H NMR (400 MHz,
;
CDCl3) d: 7.8–6.9 (13H, m, Ar), 4.3 (1H, S, >N–H), 5.5
(1H, S, CH–), 2.5 (3H, S, –CH3); 13C NMR (CDCl3) d: 43.2,
46.5, 110.2, 111.6, 117.7, 119.6, 121.4, 127.6, 128.3, 129.2,
130.2, 130.7, 131.7, 133.4, 134.2, 148.3; MS: Molecular ion peak
m/z 395; Anal. Calcd for C21 H18Cl N3OS: C, 63.71; H, 4.58; N,
10.61. Found: C, 63.07; H, 4.36; N, 10.22.
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(2-chlorophenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIf).
Yield: 67%; IR (Potassium bromide): 3365 (>N–H), 1021
(>S═O), 1630–1595 (aromatic >C═C), 1683 (>C═N–) cmꢀ1
Mp 115–117ꢁC;
;
H NMR (400 MHz, CDCl3) d7.8–6.9 (13H, m, Ar), 4.6
(1H, s, >N–H), 5.4 (1H, s, CH–); 13C NMR (CDCl3) d: 46.8,
109.8, 110.2, 111.4, 117.3, 119.8, 121.7, 126.6, 127.3, 128.6,
129.3, 130.7, 131.8, 133.4, 134.3, 146.7; MS: Molecular ion
peak m/z 416; Anal. Calcd for C20H15Cl2N3OS: C, 57.70; H,
3.63; N, 10.09. Found: C, 57.22; H, 3.12; N, 10.09
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(4-nitrophenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIc).
Yield: 63%; IR (Potassium bromide): 3334 (>N–H), 1021
(>S═O), 1632–1573 (aromatic >C═C<), 1665 (>C═N–) cmꢀ1
Mp 155–157ꢁC;
;
H NMR (400 MHz, CDCl3) d: 7.9–6.8 (13H, m, Ar), 4.4
(1H, s, >N–H), 5.6 (1H, s, CH–); 13C NMR (CDCl3) d 47.3,
109.2, 111.3, 117.3, 119.4, 121.7, 127.3, 128.3, 128.8, 129.2,
3-(2-Chlorophenyl)-4-imino-5-phenyl-2-(2-methoxyphenyl)-
2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIg). Mp 85–87ꢁC;
Yield: 66%; IR (Potassium bromide): 3379 (>N–H), 1660–1616
Table 1
Characterization data of azomethines and N-(a-Cyano-a-aryl)-methylanilines.
Entry
X
Y
Mp of azomethines (ꢁC)
Mp of N-(a-Cyano-a-aryl)-methylanilines (ꢁC)
II (a)
II (b)
II (c)
II (d)
II (e)
II (f)
II (g)
II (h)
II (i)
II (j)
II (k)
II (l)
II (m)
II (n)
II (o)
II (p)
II (q)
II (r)
II (s)
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
H
45–47
52–54
122–23
64–66
60–62
112–14
78–80
68–70
90–92
185–87
110–12
87–89
132–34
94–96
108–10
92–94
4-CH3
4-NO2
4-Cl
4-OCH3
2-Cl
2-OCH3
H
4-CH3
4-OCH3
4-Cl
4-COOH
3-NO2
2-OH
H
4-CH3
4-NO2
4-Cl
65–63
125–27
120–23
110–12
257–59
121–23
112–13
88–90
116–18
198–200
126–28
98–100
78–80
121–23
207–210
93–95
108–10
116–18
202–04
138–40
252–54
122–23
4-NO2
4-NO2
4-NO2
4-NO2
4-NO2
2-OCH3
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

1160
M. Kaur and B. Singh
Vol 51
Table 2
Characterization data of 2,3,5-triaryl-4-imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxides.
Entry
X
Y
Mp of thiadiazolidin-1-oxide (ꢁC)
Refluxing time (min)
Yield (%)
II (a)
II (b)
II (c)
II (d)
II (e)
II (f)
II (g)
II (h)
II (i)
II (j)
II (k)
II (l)
II (m)
II (n)
II (o)
II (p)
II (q)
II (r)
II (s)
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
2-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
4-Cl
H
85–87
112–14
155–57
102–04
95–97
115–17
85–87
83–85
25
30
60
40
15
55
20
28
32
22
38
39
58
45
30
28
57
38
18
69
67
63
64
68
67
67
67
62
64
66
65
64
67
69
67
64
67
63
4-CH3
4-NO2
4-Cl
4-OCH3
2-Cl
2-OCH3
H
4-CH3
4-OCH3
4-Cl
4-COOH
3-NO2
2-OH
H
4-CH3
4-NO2
4-Cl
68–70
92–94
105–07
170–72
155–57
115–17
122–24
228–30
158–160
297–99
172–73
4-NO2
4-NO2
4-NO2
4-NO2
4-NO2
2-OCH3
(>C═N–), 1021 (>S═O), 1632–1597 and 1536–1500 (aromatic
>C═C<) cm–1; 1H NMR (400 MHz, CDCl3) d: 7.8–6.7 (13H, m,
Ar), 4.6 (1H, s, >N–H–), 5.7 (1H, s, CH–), 3.8 (3H, s, –OCH3);
13C NMR (CDCl3) d: 47.5, 55.5, 110.1, 111.7, 117.8, 119.8,
121.2, 127.8, 128.8, 129.0, 130.4, 130.9, 131.9, 133.5, 134.4,
147.5; MS: Molecular ion peak m/z 411 and others prominent
peak are at m/z 271, 246, 212; Anal. Calcd for C21H18ClN3O2S:
C, 61.23; H, 4.40; N, 10.20. Found: C, 61.12; H, 4.17; N, 10.08.
3-(4-Chlorophenyl)-4-imino-2,5-diphenyl-2H,3H,5H-[1,2,5]
C21H18ClN3O2S: C, 60.94; H, 4.87; N, 10.15. Found: C, 60.23;
H, 4.12; N, 10.02.
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(4-chlorophenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIk).
Yield: 66%; IR (Potassium bromide): 3338 (>N–H), 1673
Mp 105–107ꢁC;
(>C═N–), 1630–1590 (aromatic >C═C<), 1023 (>S═O) cmꢀ1
;
1H NMR (400MHz, CDCl3) d: 8.2–6.8 (13H, m, Ar), 4.6 (1H, s,
>N–H), 5.5 (1H, s, CH–); 13C NMR (CDCl3) d: 47.8, 114.7,
115.3, 117.7, 125.4, 127.7, 128.3, 128.9, 129.7, 130.4, 131.5,
131.9, 133.6, 144.6; MS: Molecular ion peak m/z 416; Anal.
Calcd for C20H15Cl2N3OS: C, 57.42; H, 4.10; N, 10.04. Found:
C, 57.12; H, 3.92; N, 9.93.
thiadiazolidin-1-oxide (IIh).
(Potassium bromide): 3345 (>N–H), 1645 (>C═N–), 1632–1580
(aromatic >C═C<), 1021 (>S═O) cmꢀ1 1H NMR (400 MHz,
Mp 83–85ꢁC; Yield: 67%; IR
;
CDCl3) d 8.2–6.8 (14H, s, CH–), 4.2 (1H, s, >N–H), 5.6
(1H, s, CH–); 13C NMR (CDCl3) d: 48.3, 115.4, 117.6, 125.3,
125.8, 126.7, 127.3, 128.3, 128.8, 129.5, 130.5, 131.3, 131.7,
133.7, 144.2; MS: Molecular ion peak m/z 383; Anal. Calcd for
C20H16ClN3OS: C, 62.57; H, 4.73; N, 10.95.. Found: C, 62.27; H,
4.23; N, 10.12.
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(4-carboxyphenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIl).
Mp 170–72ꢁC;
Yield 66%; IR (Potassium bromide): 3379 (>N–H), 1665
(>C═N), 1630–1590 (aromatic >C═C), 1023 (>S═O); 1H
NMR (400 MHz, CDCl3) d: 8.1–6.7 (13H, m, Ar), 4.3 (1H, s,
>N–H), 5.7 (1H, s, –CH), 11.9 (1H, s, COOH); 13C NMR
(CDCl3) d: 48.3, 110.4, 111.3, 111.9, 121.7, 127.6, 128.3,
128.7, 129.6, 130.5, 130.7, 131.3, 131.7, 133.6, 134.7, 147.7,
150.7; MS: Molecular ion peak m/z 425; Anal. Calcd for
C21H16ClN3O3S: C, 58.94; H, 4.24; N, 9.82. Found: C, 58.14;
H, 4.03; N, 9.12.
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(4-tolyl)-2H,3H,5H-
[1,2,5]thiadiazolidin-1-oxide (IIi). Mp 68–70ꢁC; Yield: 62%;
IR (Potassium bromide): 3342–3312 (>N–H), 1667 (>C═N–),
1
1640–1575 (aromatic >C═C<), 1024 (>S═O) cmꢀ1; H NMR
(400 MHz, CDCl3) d: 8.1–7.1 (13H, m, Ar), 4.3 (1H, s, >N–H),
5.5 (1H, S, CH–), 2.4 (3H, s, –CH3); 13C NMR (400 MHz,
CDCl3) d: 43.6, 48.7, 110.2, 111.6, 117.3, 119.7, 121.3, 127.6,
128.7, 129.3, 130.6, 131.8, 132.3, 132.9, 133.3, 134.5, 147.2;
MS: Molecular ion peak m/z 395; Anal. Calcd for
C21H18ClN3OS: C, 63.3; H, 5.07; N, 10.56. Found: C, 62.9; H,
4.89; N, 10.12.
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(3-nitrophenyl)-2H,
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIm).
Yield: 64%; IR (Potassium bromide): 3345 (>N–H), 1645
Mp 155–157ꢁC;
(>C═N–), 1638–1587 (aromatic >C═C<), 1021 (>S═O) cmꢀ1
;
1H NMR (400 MHz, CDCl3) d: 8.1–6.8 (13H, m, Ar), 4.4 (1H, s,
>N–H), 5.6 (1H, s, CH–); 13C NMR (CDCl3) d: 44.6, 110.7,
111.4, 117.8, 119.3, 121.3, 127.4, 128.5, 129.2, 130.4, 130.8,
131.4, 133.3, 134.7, 148.3; MS: Molecular ion peak m/z 426;
Anal. Calcd for C20H15ClN4O3S: C, 56.01; H, 4.00; N, 13.06.
Found: C, 55.93; H, 3.97; N, 13.02.
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(4-methoxyphenyl)-
2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIj).
Yield: 64%; IR (Potassium bromide): 3342 (>N–H), 1672
Mp 92–94ꢁC;
(>C═N–), 1638–1573 (aromatic >C═C<), 1024 (>S═O) cmꢀ1
;
1H NMR (400 MHz, CDCl3) d: 8.0–6.9 (13H, m, Ar), 4.5 (1H, s,
>N–H), 5.4 (1H, s, CH–), 3.4 (3H, s, –OCH3); 13C NMR
(CDCl3) d: 46.7, 57.3, 110.3, 111.7, 116.6, 117.4, 119.5, 121.2,
126.4, 128.3, 129.2, 130.4, 130.7, 131.6, 133.7, 134.7, 147.7;
MS: Molecular ion peak m/z 410; Anal. Calcd for
3-(4-Chlorophenyl)-4-imino-5-phenyl-2-(2-hydroxyphenyl)-
2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIn). Mp 115–117ꢁC;
Yield: 67%; IR (Potassium bromide): 3342 (>N–H), 1665
(>C═N–), 1630–1585, 1545–1515 (aromatic >C═C<), 1024
(>S═O) cmꢀ1 1H NMR (400 MHz, CDCl3) d: 7.9–6.7 (13H,
;
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

July 2014
Synthesis of 4-Imino-2H,3H,5H-[1,2,5]thiadiazolidin-1-oxide through Cycloaddition
1161
Reaction of N-Sulphinylanilines and N-(a-Cyano-a-aryl)-methylanilines
m, Ar), 4.6 (1H, s, >N–H), 5.4 (1H, s, CH–), 9.2 (1H, s, –OH); 13
C
67%; IR (Potassium bromide): 3365 (>N–H), 1665 (>C═N–), 1023
1
NMR (CDCl3) d: 47.3, 111.7, 115.8, 116.8, 118.3, 119.5, 121.3,
127.4, 129.4, 130.4, 131.6, 132.3, 143.3; MS: Molecular ion
peak m/z 399; Anal. Calcd for C20H16ClN3O2S: C, 60.07; H,
4.54; N, 10.51. Found: C, 60.02; H, 4.23; N, 10.28.
(>S═O), 1635–1585 (aromatic >C═C<)cmꢀ1; H NMR (CDCl3)
d: 8.2–6.9 (13H, m, Ar), 4.5 (1H, s, >N–H), 5.6 (1H, s, CH–); 13C
NMR (CDCl3) d: 47.3, 110.1, 111.7, 119.8, 121.2, 127.4,
128.3, 128.8, 129.2, 130.2, 130.7, 131.7, 133.4, 134.2,
147.8; MS: Molecular ion peak m/z 426; Anal. Calcd for
C20H15Cl N4O3S: C, 56.27; H, 3.54; N, 13.12. Found: C,
56.12; H, 3.12; N, 13.02.
3-(4-Nitrophenyl)-4-imino-2,5-diphenyl-2H,3H,5H-[1,2,5]
thiadiazolidin-1-oxide (IIo). Mp 122–124ꢁC; Yield: 69%; IR
(Potassium bromide): 3373 (>N–H), 1665 (>C═N–), 1024
(>S═0), 1630–1585 and 1545–1515 (aromatic >C═C<) cmꢀ1
;
3-(4-Nitrophenyl)-4-imino-5-phenyl-2-(2-methoxyphenyl)-2H,
1H NMR (400 MHz, CDCl3) d: 8.0–6.8 (14H, m, Ar), 4.4 (1H,
s, >N–H), 5.5 (1H, s, CH–); 13C NMR (CDCl3) d: 46.3, 112.2,
114.4, 117.3, 119.7, 126.3, 127.4, 128.3, 128.8, 130.7, 130.9,
131.5, 133.4, 134.3, 148.2; Ms: Molecular ion peak m/z 392;
Anal. Calcd for C20H16N4O3S: C, 61.21; H, 4.11; N, 14.28.
Found: C, 61.12; H, 4.02; N, 14.12.
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIs).
Yield: 63%; IR (Potassium bromide): 3375 (>N–H), 1668
Mp 172–173ꢁC;
(>C═N–), 1024 (>S═O), 1630–1590 (aromatic >C═C<) cmꢀ1
;
1H NMR (400 MHz, CDCl3) d: 8.0–6.9 (13H, m, Ar), 3.6
(3H, s, –OCH3), 4.6 (1H, s, >N–H), 5.5 (1H, s, CH–); 13C
NMR (CDCl3) d: 46.7, 55.2, 110.1, 111.3, 117.3, 119.3, 121.7,
127.4, 127.9, 128.8, 129.0, 130.7, 131.3, 133.4, 134.2, 143.7;
MS: Molecular ion peak m/z 422; Anal. Calcd for C21H18N4O4S:
C, 59.42; H, 4.75; N, 13.20. Found: C, 59.12; H, 4.27; N,
13.00.
3-(4-Nitrophenyl)-4-imino-5-phenyl-2-(4-tolyl)-2H,3H,5H-
[1,2,5]thiadiazolidin-1-oxide (IIp).
Mp 228–230ꢁC; Yield:
67%; IR (Potassium bromide): 3375 (>N–H), 1675 (>C═N–),
1
1021 (>S═O), 1635–1590 (aromatic >C═C<) cmꢀ1; H NMR
(400 MHz, CDCl3) d: 7.9–6.9 (13H, m, Ar), 2.5 (3H, s, –CH3),
4.5 (1H, s, >N–H), 5.6 (1H, s, CH–); 13C NMR (CDCl3) d:
44.7, 48.3, 110.2, 111.4, 117.7, 119.3, 121.4, 127.7, 128.6,
129.3, 129.7, 130.6, 131.7, 133.4, 134.4, 147.5; MS: Molecular
ion peak m/z 406; Anal. Calcd for C21H18N4O3S: C, 62.05; H,
4.46; N, 13.78. Found: C, 61.93; H, 4.12; N, 13.27.
Acknowledgment. The authors wish to thank NIPER (Mohali),
SAIF (PU) for spectral studies.
3-(4-Nitrophenyl)-4-imino-5-phenyl-2-(4-nirophenyl)-2H,3H,
5H-[1,2,5]thiadiazolidin-1-oxide (IIq). Mp 158–160ꢁC; Yield:
64%; IR (Potassium bromide): 3360 (>N–H), 1673 (>C═N–),
REFERENCES AND NOTES
[1] Kanaka, Y.; Nagasawa, C.; Nakai, H.; Sato, Y.; Ogiwara, H.;
Mizoguchi, T. Heterocycles 1975, 3, 553.
[2] Zoller, U.; Rona, P. Tetrahedron Lett 1985, 26, 2813.
[3] Singal, K. K.; Singh, B.; Raj, B. Synthetic Commun 1999, 29, 911.
[4] Singal, K. K.; Singh, B.; Rehalia, K. S. Indian J Chem 1988,
27B, 643.
1
1024 (>S═O), 1632–1593 (aromatic >C═C<) cmꢀ1; H NMR
(400 MHz, CDCl3) d: 8.1–6.8 (13H, m, Ar), 4.6 (1H, s, >N–H),
5.5 (1H, s, CH–); 13C NMR (CDCl3) d: 47.8, 111.2, 111.8,
116.3, 117.8, 119.2, 121.4, 126.4, 127.2, 127.9, 128.8, 129.3,
130.4, 130.9, 131.3, 133.2, 134.7, 146.4; MS: Molecular ion
peak m/z 437. Anal. Calcd for C20H15N5O5S: C, 54.91; H, 3.46;
N, 16.01. Found: C, 54.17; H, 3.11; N, 16.00.
[5] Harris, G. H.; Harriman, B. R.; Wheller, K. W. J Amer Chem
Soc 1946, 68, 846.
[6] Layer, R. W. Chem Rev 1963, 63, 489.
3-(4-Nitrophenyl)-4-imino-5-phenyl-2-(4-chlorophenyl)-2H,
[7] Michaelis, A.; Hertz, R. Ber Dt Chem Qer 1890, 23, 3480.
[8] Bottigen, C. Ber Dt Chem Ges 1979, 11, 1407.
3H,5H-[1,2,5]thiadiazolidin-1-oxide (IIr). Mp above 300ꢁC; Yield:
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet